低温对大鼠睾丸扭转复位后生殖细胞凋亡的影响

目的 探讨低温对大鼠睾丸扭转复位后生殖细胞凋亡的影响。方法 24只健康青春期SD雄性大鼠随机分为三组:A组为睾丸扭转组,B组为睾丸扭转加低温组,C组为对照组。建立单侧睾丸扭转模型。术后第14天采集睾丸。原位缺口末端标记法(TUNEL)检测其生殖细胞凋亡指数(AI),光镜下观察睾丸组织学变化。结果 B组AI明显低于A组(P<0.01),而高于C组(P<0.01)。结论 低温能够提高扭转睾丸耐缺血能力,减少睾丸扭转复位后生殖细胞凋亡。     

低温联合地塞米松对大鼠睾丸扭转复位后eNOS表达及生精细胞凋亡的影响

目的:探讨低温联合地塞米松对睾丸扭转复位后的保护作用,以及对eNOS表达及生精细胞凋亡的影响。方法:将80只青春期SD大鼠随机分为4组,每组20只。4组大鼠分别扭转左侧睾丸720°2 h,建立单侧睾丸扭转模型,随后各组做如下处理,A组:常温+生理盐水、B组:低温+生理盐水、C组:低温+地塞米松、D组:常温+地塞米松;术后48 h采集睾丸,通过HE染色光镜观察睾丸组织病理学改变、免疫组化法检测eNOS表达、TUNEL法检测睾丸生精细胞凋亡。结果:HE染色光镜下见4组大鼠扭转侧睾丸组织均有不同程度损伤,其中A组睾丸损伤最明显,其余3组扭转侧睾丸得到不同程度保护;睾丸组织eNOS免疫组化检测结果:A组扭转侧(左侧)睾丸组织阳性细胞数及阳性细胞着色强度明显强于B、C、D 3组,差异具有显著性(P<0.05、P<0.01、P<0.01);凋亡细胞染色:细胞核呈深棕黄色或棕褐色,A组扭转侧(左侧)睾丸可见大量生精细胞凋亡,凋亡指数AI(31.12±4.68)明显高于B组(16.58±6.22)(P<0.05)及C(8.60±1.15)、D组(13.52±3.06)(P<0.01)。结论:睾丸扭转复位后的缺血再灌注损伤可导致生精细胞凋亡增加、睾丸生殖能力下降;应用低温联合地塞米松能显著增强睾丸组织的抗损伤能力,较好地保护了扭转复位后睾丸的生精功能。     

低温联合地塞米松对大鼠睾丸扭转复位后ICAM1表达的影响及生精功能的保护作用

目的:探讨低温联合地塞米松对大鼠睾丸扭转复位后的生精功能的保护作用,以及对细胞间粘附分子1(ICAM1)表达的影响。方法:将100只青春期的雄性SD大鼠(体重140~160 g)随机分为4组,每组25只。4组大鼠分别扭转左侧睾丸720°2 h,建立单侧睾丸扭转动物模型,各组做如下处理,A组:常温+生理盐水;B组:低温+生理盐水;C组:常温+地塞米松;D组:低温+地塞米松;术后48 h采集睾丸,通过HE染色光镜观察睾丸组织病理学改变、TUNEL法检测睾丸生精细胞的凋亡、Western印迹检测ICAM1的表达。结果:HE染色光镜下见4组大鼠扭转侧睾丸组织均有不同程度损伤,其中A组睾丸损伤最为明显,其余3组扭转侧睾丸得到不同程度保护;睾丸组织ICAM1 Western印迹检测结果:A组扭转侧(左侧)睾丸组织ICAM1蛋白表达量(0.68±0.03)高于B组(0.49±0.06)、C组(0.46±0.09)、D组(0.17±0.08),差异具有显著性(P0.05、P0.05、P0.01);凋亡细胞染色:细胞核呈深棕黄色或棕褐色,A组扭转侧睾丸可见大量生精细胞凋亡,凋亡指数AI[(33.13±3.21)%]明显高于B组[(17.12±5.23)%](P0.05)、C组[(14.13±2.03)%](P0.05)及D组[(9.05±1.03)%](P0.01)。结论:低温联合地塞米松能显著增强睾丸组织抗损伤能力,较好地保护扭转复位后睾丸的生精功能及降低ICAM1的表达。     

黄芪对大鼠睾丸扭转/复位模型保护作用的研究

目的:探讨黄芪注射液对大鼠睾丸扭转/复位模型的保护作用。方法:将30只健康雄性Wistar大鼠分为3组。分别为假手术对照组(A组,n=10);睾丸扭转/复位组(B组,n=10);睾丸扭转/复位+腹腔内注射黄芪注射液组(C组,n=10)。按Turner法建立睾丸扭转模型,喂养至术后7d处死,切取扭转侧睾丸检测凋亡指数(AI)及谷胱甘肽过氧化物酶活力及丙二醛含量。结果:A、B、C三组扭转侧睾丸AI分别为5.82±1.21、36.18±8.40、20.39±3.57,B、C组明显高于对照组(P(0.05),B组明显高于C组(P(0.05)。A、B、C三组扭转侧睾丸谷胱甘肽过氧化物酶活力分别为48.03±2.01、30.93±1.25、38.44±1.06U/mg;丙二醛含量分别为1.43±0.17、3.98±0.36、2.57±0.53nmol/ml,三组之间比较均有显著性差异(P(0.05)。结论:黄芪注射液可明显减少扭转侧睾丸生殖细胞凋亡,保护谷胱甘肽过氧化物酶活力,减轻脂质过氧化程度。     

单侧睾丸扭转后生精细胞凋亡的分子途径

目的:研究大鼠单侧睾丸扭转复位后生精细胞凋亡的分子机制。方法:雄性SD大鼠16只,随机分为对照组和扭转组,每组8只。建立睾丸扭转动物模型(720°2h),术后24h留取手术侧睾丸。应用流式细胞术检测生精细胞凋亡和各级生精细胞计数,应用RT-PCR技术对Fas/FasL mRNA和Bax mRNA进行半定量分析,Western印迹技术检测细胞色素C含量。结果:两组间生精细胞凋亡及各类生精细胞计数均有显著性差异(P<0.01)。扭转组FCM直方图呈现高大凋亡峰,单倍体和四倍体细胞群计数下降,Fas/FasL mRNA和Bax mRNA表达上调,同时细胞质中细胞色素C含量亦明显升高,与对照组相比其差异均有显著性(P均<0.01)。结论:睾丸扭转复位后生精细胞凋亡存在着外源性和内源性两条基本途径。凋亡相关分子Fas/FasL表达上调和Bax介导的细胞色素C释放可能是睾丸扭转后生精细胞凋亡的重要环节。     

己酮可可碱对大鼠睾丸扭转复位后生精功能的保护

目的:探讨己酮可可碱(PTX)对大鼠睾丸扭转复位后生精功能的保护作用。方法:雄性SD大鼠24只,随机分成3组,每组8只,建立睾丸扭转动物模型。第Ⅰ组为假手术组(扭转720°后立即复位),第Ⅱ、Ⅲ组扭转720°2 h,于复位前15 m in分别静脉注射生理盐水和PTX,术后24 h留取手术侧睾丸。应用流式细胞术(FCM)检测各组生精细胞凋亡和各级生精细胞计数,采用硫代巴比妥酸法测定丙二醛(MDA)含量,化学比色法测定组织内总抗氧化能力(T-AOC)。结果:第Ⅲ组应用PTX后与第Ⅱ组相比,生精细胞凋亡明显减少(399.50±33.31vs1221.75±132.48,P<0.01),单倍体和四倍体细胞群计数显著增多(5554.13±441.28vs4102.35±206.98;1906.00±200.72vs1711.63±144.55,P均<0.01;),T-AOC明显回升(32.52±2.86vs22.76±3.73,P<0.01),MDA含量下降(1.78±0.20vs3.98±0.36,P<0.01),其差异均有显著性(P<0.01)。结论:己酮可可碱对睾丸扭转复位后的生精功能具有明显的保护作用。     

单侧睾丸扭转对生殖细胞凋亡及黄芪保护作用的实验研究

目的观察大鼠单侧睾丸扭转／复位后患侧和对侧睾丸生精细胞凋亡情况,探讨单侧睾丸扭转／复位后生殖能力下降的机制以及黄芪注射液对其再灌注损伤的保护作用。方法将40只健康雄性Wistar大鼠分为4组,分别为假手术对照组（A组）,睾丸扭转／复位组（B组）,睾丸扭转／复位＋单次腹腔内注射黄芪注射液组（C组）及扭转／复位十连续腹腔内注射黄芪注射液组（D组）,每组10只。按Turner法建立睾丸扭转／复位模型,所有大鼠均在同等条件下喂养至术后7d处死,切取双侧睾丸后检测凋亡指数。结果扭转侧睾丸生殖细胞凋亡指数（AI）A组（5．82±1．21）与B组（36．18±8．40）、C组（20．39±3．57）、D组（11．61±5．12）相比差异有显著性（P〈0．05）,B组明显高于C组及D组（P〈0．05）,C组与D组相比差异有显著性（P〈0．05）;B组对侧睾丸（12．95±3．06）与C组（9．45±1．71）、D组（7．56±1．06）两组对侧睾丸AI相比差异有显著性（P〈0．05）,C、D两组对侧睾丸AI差异有显著性（P〈0．05）。结论单侧睾丸扭转可致患侧和对侧睾丸生精细胞凋亡明显增加,黄芪注射液可明显减少双侧睾丸生殖细胞凋亡,连续应用黄芪注射液优于单次应用。     

茶多酚对大鼠睾丸扭转/复位模型保护作用的研究

目的:探讨茶多酚对大鼠睾丸扭转/复位模型的保护作用。方法:将24只健康雄性Wistar大鼠随机分为3组,每组8只。第Ⅰ组为假手术组(切开左侧阴囊游离睾丸,但不予扭转),第Ⅱ、Ⅲ组扭转左侧睾丸720°6h,分别于扭转复位前30min腹腔注射生理盐水和茶多酚,术后连续3d分别以低剂量维持。3组大鼠喂养至术后第5天处死,切取左侧扭转睾丸检测睾丸组织中超氧化物歧化酶(SOD)和丙二醛(MDA)含量;以原位缺口末端标记法(TUNEL)检测生精细胞凋亡指数(AI)。结果:Ⅰ、Ⅱ、Ⅲ3组左侧扭转睾丸组织SOD活力分别为(285.00±22.51)、(242.00±17.62)、(261.00±10.01)nU/mg;MDA含量分别为(1.81±0.20)、(4.34±0.34)、(2.94±0.38)nmol/mg;3组之间比较均有显著性差异。Ⅰ、Ⅱ、Ⅲ3组左侧扭转睾丸生精细胞凋亡指数(AI)分别为6.64±1.82、55.23±6.46、31.84±5.56,第Ⅲ组与第Ⅱ组相比,其生殖细胞凋亡明显减少(P<0.05)。结论:茶多酚对因睾丸扭转导致的缺血再灌注损伤具有保护作用。     

黄芪注射液对大鼠扭转复位后睾丸组织的保护作用

目的:探讨黄芪注射液对雄性Wistar大鼠扭转复位后睾丸的保护作用。方法:30只大鼠随机分为假手术组(A组)、睾丸扭转复位组(B组)、黄芪注射液治疗组(C组),每组10只,Turner法建立单侧睾丸扭转复位模型,原位缺口末端标记法检测各组睾丸组织中生殖细胞凋亡,化学比色法测定超氧化物歧化酶(SOD)和丙二醛(MDA)含量。结果:黄芪注射液治疗组与睾丸扭转复位组比较,SOD含量明显升高,MDA含量明显降低,生精细胞凋亡指数明显降低。睾丸扭转复位组、黄芪注射液治疗组与假手术对照组比较,SOD含量明显降低,MDA含量明显升高,生精细胞凋亡指数明显升高。结论:黄芪注射液可减少大鼠睾丸扭转复位后睾丸组织的双侧睾丸生殖细胞凋亡,对扭转复位后睾丸生殖细胞有保护作用。其机理可能与提高抗氧化酶活性及减少氧自由基的产生从而减轻大鼠睾丸扭转复位后的缺血再灌注损伤有关。     

睾丸扭转后生精细胞凋亡与iNOS基因表达

本文研究了睾丸扭转复位后生精细胞凋亡与iNOS基因表达的关系。采用大鼠建立左侧睾丸扭转复位模型(720,2h)。用TUNEL法和免疫组化SP法分别检测扭转复位后第五天生精细胞凋亡和iNOS基因表达。研究发现凋亡主要见于染色质降解的生精细胞(初级精母细胞和圆形精子细胞)。问质细胞和支持细胞未见凋亡发生。iNOS表达见于各级生精细胞,在染色质降解的生精细胞(即凋亡细胞)强表达。本研究表明睾丸扭转复位后生精细胞凋亡增加与iNOS基因表达密切相关。睾丸局部NO生成异常可能是生精细胞凋亡增加的原因之一。     

低温对大鼠睾丸扭转后睾丸抗氧化能力影响的研究

目的:探讨低温对睾丸扭转后其抗氧化能力的影响。方法:24只健康青春期SD雄性大鼠随机分为3组:A组为睾丸扭转组,B组为睾丸扭转加低温组,C组为对照组,每组8只。建立单侧睾丸扭转模型。术后第14d采集睾丸。化学比色法测定其总抗氧化能力(T-AOC)和丙二醛(MDA)的含量。光镜观察睾丸组织学变化。结果:B组T-AOC明显高于A组(P<0.01),而低于C组(P<0.01);B组MDA含量低于A组(P<0.01),而高于C组(P<0.05)。结论:低温可抑制睾丸扭转复位后氧自由基的产生及其引发的脂质过氧化反应,提高扭转睾丸的生存力。     

Effects of hypothermia and pentoxifylline on the adnexal torsion/detorsion injuries in a rat testis model

This study was designed to investigate the effects of separate and combined administration of hypothermia and pentoxifylline to preserve the effects on the testicles in an experimental model of testicular torsion/ detorsion injuries in rats. Forty male adult Wistar rats were randomly divided into five groups, control, torsion/detorsion (TD), torsion/detorsion/hypothermia (TD+ICE), torsion/detorsion received of pentoxifylline (40mg/kg, ip) (TD+PTX) and torsion/detorsion/hypothermia/PTX (TD+ICE+PTX). Left testicular torsion (TT) was performed for 4 and half hours, and ice fragments have been used at the beginning of torsion. After the reperfusion period (a week), oxidative maker's serum levels, testosterone hormone, sperm parameters, and histopathological and gene expression evaluations have been performed. Significant adverse changes were observed in the TD group for histological variables, sperm count, oxidative marker, testosterone hormone, Bax, BCL2 and caspase-3 expression. The parameters studied in the group receiving PTX improved in comparison with the TD group, while macroscopical parameters of both the hypothermia and PTX+ICE groups were not different compared with the TD group. The results revealed that PTX, as an antioxidant component, was protective against testicular torsion, while hypothermia and hypothermia plus PTX did not exhibit this property, which may have been due to the duration of hypothermia (4 hr) or reperfusion period.     

Effects of oral zinc administration on long‐term ipsilateral and contralateral testes damage after experimental testis ischaemia–reperfusion

The purpose of this study was to examine potential long‐term post‐torsion changes that can occur in the histopathology, biochemistry and spermatogenesis of both torsioned and nontorsioned opposite testes. The study also determines the effect of zinc (Zn) administration on the testicular torsion/detorsion (T/D) damage on both testes. Forty‐eight male rats, divided equally into eight groups: (SHAM), (SHAM+,Zn+), (T/D+, Zn? 1 month), (T/D+,Zn? 2 months), (T/D+,Zn? 3 months), (T/D+,Zn+ 1 months), (T/D+,Zn+ 2 months), (T/D+,Zn+ 3 months), have been used. Drug administration was carried out by adding 100 μg (0.016 ml/rat) Zn per rat to drinking water in related groups. Testicular damage decreased superoxide dismutase (SOD) and glutathione (GSH) and increased malondialdehyde (MDA) in the testis tissues of rats, while Zn administration increased SOD and GSH and decreased MDA in the testis tissues in comparison with the SHAM group. The beneficial effect of zinc sulphate was more evident on the nonrotated testis than the rotated testis. In the histopathological study, a significant decrease in torsion and detorsion injuries was observed in the treatment groups compared to the torsion and detorsion groups. We found a protective effect of zinc sulphate on oxidative stress as a result of T/D injuries in rats, especially for the nonrotated testis; results were supported histopathologically.     

大鼠一侧睾丸扭转对侧睾丸改变的实验研究

目的 :研究一侧睾丸扭转 (UTT)后对侧睾丸组织学及生精细胞凋亡的改变 ,以明确UTT后对侧睾丸是否存在损伤。　方法 :SD雄性大鼠 6 0只 ,随机分为实验组 (n =4 8)及对照组 (n =12 )。实验组采用Turner方法建立左侧睾丸扭转模型 ,于扭转后 6h处死 4只 ,其余 4 4只再分为扭转睾丸复位及切除组 ,分别于术后 1d、1周、4周处死7～ 8只 ,取睾丸组织进行组织学及生精细胞凋亡的检测。　结果 :UTT复位后对侧睾丸组织学发生明显改变 ,生精细胞凋亡指数明显高于对照组 (P <0 .0 5 )。扭转睾丸切除后对侧睾丸变化不明显。　结论 :UTT可引起对侧睾丸损伤 ,其机制可能与再灌注有关 ,扭转睾丸切除可防止或减轻对侧睾丸的损伤     

Immunohistopathology of the contralateral testis of rats undergoing experimental torsion of the spermatic cord

Aim:To evaluate the immunohistopathological changes in the contralateral testis of rats after an experimental sper-matic cord torsion.Methods:Male Sprague-Dawley rats of 45-50 days old were subjected to a 720° unilateralspermatic cord torsion for 10,30 and 80 days(experimental group,E),respectively or sham operation(controlgroup,C).Histopathology of the contralateral testis as well as germ cell apoptosis were studied using the TerminalDeoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling(TUNEL)technique.The number of testicularlymphocytes,mast cells and macrophages,and the expression of tumor necrosis factor-α(TNF-α)and its receptor(TNFR1)in testicular cells of the contralateral testis were quantified by histochemistry and immunohistochemistry.TNF-α concentration in testicular fluid was determined by ELISA.Results:In the contralateral testis of rats fromthe E group,the maximal degree of damage of the germinal epithelium was seen 30 days after torsion.At this time weobserved in the E group vs.the C group increases:(i)the number of testicular T-lymphocytes;(ii)the number oftesticular mast cells and macrophages;(iii)the percentage of macrophages expressing TNF-α:(iv)TNF-α concen-tration in testicular fluid;(v)the number of apoptotic germ cells;and(vi)the number of TNFR1~ germ cells.Conclusion:Experimental spermatic cord torsion induces,in the contralateral testis,a focal damage of seminiferous tubulescharacterized by apoptosis and sloughing of germ cells.Results suggest humoral and cellular immune mediatedtesticular cell damage in which macrophages and mast cells seem to be involved in the induction of germ cell apoptosisthrough the TNF-α/TNFR1 system and in the modulation of the inflammatory process.(Asian J Andro12006 Sep;8:576-583)     

The effects of human chorionic gonadotropin treatment on the contralateral side in unilateral testicular torsion

BACKGROUND/PURPOSE: Unilateral testicular torsion can cause histologic damage, consisting of aspermatogenesis and tubular atrophy, in the contralateral testis human chorionic gonadotropin (HCG) treatment is widely used in undescended testis, and has been shown to improve histomorphometric alterations beside the testicular descent. However, the role of HCG in testicular torsion has not been investigated before. Therefore, this experimental study was conducted to evaluate the effects of HCG treatment on contralateral testicular histology and function in unilateral testicular torsion. METHODS: Forty adult male Wistar rats were randomized into 4 groups: SHAM, SHAM+HCG, TORSION, and TORSION+HCG. Torsion was created by twisting the righ testis 720 degrees and maintained by fixing it to the scrotum. HCG treatment started 24 hours after the torsion at a dose of 100 IU/kg, twice weekly for three weeks. Left orchiectomy was performed one month after the torsion and removed testes were immersed in Bouin's fixative for histopathological evaluation. Mean seminiferous tubule diameter (MSTD) was measured and Johnsen's score was calculated. Blood samples were taken for assaying serum testosteron level. RESULTS: Unilateral testicular torsion resulted in a significant decrease in spermatogenesis and MSTD on the contralateral side. Serum testosteron level was also reduced. HCG treatment improved these parameters in the contralateral 'untwisted' testis beside the serum testosteron. CONCLUSIONS: Our data demonstrates that unilateral testicular torsion adversely effects its counterpart. HCG treatment improves contralateral histomorphometric alterations and serum testosteron in unilateral torsion.     

Effects of Hypothermia, Potassium, and Verapamil on the Action Potential Characteristics of Canine Cardiac Purkinje Fibers

Background: Hypothermia may induce hypokalemia and increase Intracellular Calcium2+ by affecting serum Potassium sup + and Calcium2+ fluxes across the cell membrane. These ionic alterations may significantly change the electrophysiologic characteristics of the cardiac action potential and may induce cardiac arrhythmias. The current study was undertaken to determine whether electrophysiologic changes in Purkinje fibers induced by hypothermia could be reversed by manipulating the extracellular Potassium sup + and transmembrane Calcium2+ fluxes by Calcium2+ channel blockade with verapamil.

Methods: A conventional microelectrode method was used to determine the effects of hypothermia (32 + 0.5 degrees Celsius and 28 + 0.5 degrees Celsius) and various external Potassium sup + concentrations ([Potassium sup +]o) (2.3, 3.8, and 6.8 mM) on maximum diastolic potential, maximum rate of phase 0 depolarization (Vmax), and action potential duration (APD) at 50% (APD50) and at 95% (APD95) repolarization in isolated canine cardiac Purkinje fibers. To evaluate the contribution of the slow inward Calcium2+ current to action potential changes in hypothermia, the experiments were repeated in the presence of the Calcium2+ -channel antagonist verapamil (1 micro Meter).

Results: Variations of [Potassium sup +]o induced the expected shifts in maximum diastolic potential, and hypothermia (28 degrees Celsius) induced moderate depolarization, but only when [Potassium sup +]o was *symbol* 3.9 mM (P < 0.05). Hypothermia decreased Vmax at all [Potassium sup +]o studied (P < 0.05). Regardless of the temperature, Vmax was not affected by verapamil when [Potassium sup +]o *symbol* was 3.9 mM, but at 6.8 mM [Potassium sup +]o in hypothermia Vmax was significantly lower in the presence of verapamil. Hypothermia increased both the APD50 and the APD95. The effects of verapamil on APD were temperature and [Potassium sup +] sub o dependent; between 37 degrees Celsius and 28 degrees Celsius with 2.3 mM [Potassium sup +]o in the superfusate, verapamil did not affect APD. At 28 degrees Celsius in the presence of verapamil, the APD sub 50 and APD95 decreased only if the [Potassium sup +]o was *symbol* 3.9 mM.     

Dose-dependent protective effect of sildenafil citrate on testicular injury after torsion/detorsion in rats

This experiment was designed to investigate the effect of sildenafil citrate on testicular injury after unilateral testicular torsion/detorsion (T/D). Thirty-seven adult male Wistar albino rats were divided into four groups: sham operated group (group 1), T/D+ saline (group 2), T/D+ 0.7 mg sildenafil citrate (group 3) and T/D+ 1.4 mg sildenafil citrate (group 4). Testicular torsion was created by rotating the right testis 720° in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. The level of GSH (P < 0.05) in the testis in the group 2 were significantly lower (P < 0.05) and the levels of MDA and NO (P < 0.01 for both) in the testis were significantly higher when compared with those of the group 1. Administration of low dose sildenafil citrate prevented the increases in MDA and NO levels and decreases in GSH values induced by testicular torsion. However, administration of high dose sildenafil citrate did not have any effect on these testicular tissue parameters (P > 0.05). Also, mean values of seminiferous tubules diameters, germinal cell layer thicknesses and mean testicular biopsy score were significantly better in group 3 than groups 2 and 4. These results suggest that T/D injury occurred in testis after unilateral testicular T/D and that administration of low dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular torsion. Sildenafil citrate probably acts through reduction of reactive oxygen species and support antioxidant enzyme systems.     

Long-term protective effects of hypothermia on reperfusion injury post-testicular torsion

OBJECTIVE: As many as two-thirds of salvaged testes post-torsion will atrophy within 2 years. Subsequent testicular damage is due at least in part to an ischaemia/reperfusion injury. Thus we analysed the long-term protective effects of subjecting the ischaemic testis to hypothermia in an attempt to prevent or attenuate subsequent testicular damage. MATERIAL AND METHODS: Forty male Sprague-Dawley rats (mean age 97 days; mean weight 408 g) were randomized to one of two groups. The left testis was removed as a control and the right testis was subjected to torsion through 720 degrees in a clockwise direction and maintained in this position for 3 h. Half of the models were subjected to hypothermia by submerging the testis in a cooling bath, which was kept at a constant temperature of 2-4 degrees C for the final hour prior to detorsion. Testes were retrieved at 1 and 12 weeks and examined by a single blinded pathologist using the following histological criteria: mean seminiferous tubular diameter, mean tubular wall thickness (MTWT) and Johnsen's score. RESULTS: Histological examination revealed significant injury after 1 week of reperfusion in both groups. However, after 12 weeks of reperfusion there was a marked benefit seen in the testes subjected to hypothermia. MTWT (p=0.007) and Johnsen's score (p=0.05) were significantly better in the cooled testes after 12 weeks of reperfusion. CONCLUSION: Hypothermia reduces the degree of long-term testicular damage post-torsion and, if applied in clinical practice, may improve long-term salvage rates.